Firstly I have to say I hate these kind of posts! I have had my S4 for around three months now and absolutely love it. I went into S4 ownership with my eyes open and it is averaging around 19mpg for my short commute to work which is roughly where it should be (I think) however on a longer journey over Christmas (approx. 130 miles each way) it has only averaged 23mpg which I think is low, the book says it should have been up nearer to 30mpg. What are other people averaging? Do you think there might be a problem with it? It's due a major service shortly but had plugs done last year.